JPH0567344B2 - - Google Patents

Abstract

The invention relates to a device for uniform distribution of a viscous medium over the width of a web-like moving substrate.According to the invention the device comprises a medium outflow slit (24, 25) which is delimited by walls (34, 35), whereby the slit-wall height dimension is at least 25 times the slit-width dimension and in particular 50-150 times the slit width dimension. The invention also relates to a method for coating a moving substrate with use of such a device and to a substrate which is coated with use of a device according to the invention.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for uniformly distributing a viscous medium onto a web-like substrate moving primarily perpendicularly to the apparatus, the invention being directed to an apparatus for uniformly distributing a viscous medium onto a web-like substrate moving primarily perpendicularly to the apparatus; The present invention relates to a supply means comprising a medium distribution space and an outflow slit adjacent to the distribution space.

Prior art and its problems A device of this type is disclosed in Dutch patent application no. 8201505 in the name of the applicant.

The following terms are used in this application:

- Slit length: This refers to the dimension of the outflow slit measured along the length (axis) of the media distribution device.

- Slit wall height: This refers to the dimension of the wall which delimits the extent of the outlet slit, viewed in the direction of flow of the medium, to the smallest dimension at any position along the length of the slit.

- Slit width: this refers to the distance between the walls that defines the extent of the outflow slit to the smallest dimension at any point along the length of the slit.

Using the known device, a viscous medium can be distributed across the width of a moving web-like substrate. The device has a rod-like appearance and the central axis of the device is oriented approximately perpendicular to the direction of movement of the substrate to which the media is applied. The device is equipped with two outlet slits and has the purpose of distributing a uniform medium across the width of the moving medium. however,
Such uniform distribution of the medium is not always completely achieved in many cases. This is because the adjustment of each slit to obtain the required local outflow resistance is very delicate, and the slit adjustment can change during operation due to factors such as media pressure, temperature changes, device distortion, etc. Due to gender.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems.

In order to achieve this object, the present invention uniformly distributes a viscous medium in the width direction of a web-like base material that moves substantially perpendicularly to the axis of a rod-shaped device. The device comprises a medium supply means, at least one medium distribution space, an outflow slit connected to the distribution space, and a medium fed from the slit in contact with the surface of the substrate. the dimension of the wall delimiting the area of the outlet slit (height of the slit wall), viewed in the direction of flow of the medium, is at least 25 times the width of the slit; The present invention provides a dispensing device to a substrate having the following characteristics.

In particular, the ratio of the slit wall height to the slit width is
50 to 150 is desirable.

Furthermore, according to the invention, by designing a device of the above type in which said ratio is at least 25, and in particular between 50 and 150, a very important improvement in the uniformity of distribution is achieved, as detailed below. Ru.

The slit wall height and slit width are typically constant over the slit length.

However, in some cases and depending on the media, it may be necessary to vary the slit wall height over the slit length while keeping the slit width constant in order to obtain the desired distribution of the media. Further, in some cases, it may be necessary to change the slit width over the entire slit length while keeping the slit wall height constant.

However, the ratio of slit wall height to slit width must in all cases be at least 25 to avoid the problems associated with slit adjustment mentioned at the outset.

With the device according to the invention as described above, due to the adjusted slit width, no local displacements in the final distribution result on the substrate can be detected any longer. In order to obtain maximum adjustment of the slit width, it is advantageous to use spacers. Due to the sensitivity of some pressure media, it is desirable that these spacers have no sharp edges, and best results are obtained if they are located upstream of the outlet face of the slit.
It is extremely preferable that it be located at least half of the upstream side of the slit-like space.

In many cases, it is not necessary for the device to eject the medium over the entire length measured perpendicular to the direction of movement of the substrate. In an advantageous embodiment of the device according to the invention in this regard, the area of the outflow slit is
It can be delimited in the direction perpendicular to the outflow direction of the medium by blocking means located in the collection space leading to the outflow slit. The blocking means can be formed by a sliding piece that is fitted into the collection space. The blocking means are formed by a short sliding piece fitted into the collection space and, depending on the orientation of the device, the remaining length can be formed by a flexible hose that can be expanded for the blocking action. can.

With said blocking means, the result is that the outflow surface is limited in a direction perpendicular to the flow direction of the medium.

For certain applications, which will be explained in more detail below, it is highly advantageous if the sliding piece or pieces used are provided with a partition wall upstream of the substrate and extending perpendicularly to the substrate. be.

The present invention can further provide an apparatus for coating a moving substrate with a viscous medium by using the apparatus in an appropriate manner. This coating is
It can be done in a fixed pattern as needed,
Furthermore, it can also be carried out in combination with coating means operating in a fixed pattern.

The media dispensing device of the present invention provides a media ejection opening that abuts against the inner wall surface of the stencil when a foamed media needs to be applied to a moving substrate using a known rotating screen printing stencil. It can be used very advantageously. Rotary screen printing stencils of this type can be non-patterned stencils when the foam medium is applied in a uniform coating layer to the substrate, such as in a textile web. The stencil used will have a pattern if the foam medium is applied to form a pattern.

In another embodiment of the device according to the invention, the foamed medium is supplied upstream of the doctor blade and the foamed medium is moved such that the medium discharge opening of the medium distribution device is arranged on top of the substrate. distributed on the substrate. The two previously described embodiments of the invention differ not only with respect to the coating means used in the form of a stencil and a doctor blade. There are also differences regarding foam media. If a stencil is used in which the medium ejection openings abut against the inner wall surface of the stencil, the medium is forced into the stencil in an unexpanded state through the perforated portions of the stencil. In the example shown later,
As it exits the front section of the doctor blade, the media is given an opportunity to fully expand, and the expanded foam media is acted upon by the doctor blade to form a coating layer.

The apparatus described above is not in any way limited to dispensing foamy media onto a substrate and coating the substrate with foamy media. A variety of viscous media can be successfully treated using the dispensing device of the present invention.
In the substrate obtained by coating with a viscous medium,
The coating can be applied in a pattern if desired, and the substrate can subsequently be provided with the desired finish, if desired. The uniformity of the media distribution across the substrate is very characteristic when the coating is carried out using one or more of the above-mentioned distribution devices according to the invention.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

First of all, FIG. 1 shows a conventional dispensing device 1 with dispensing spaces 3 and 4, a body 2 with slit-like outlet surfaces 5 and 6, as well as a conventional medium collection space and an opening 8 for medium discharge. The dimensional adjustment of the slit-like outlet surfaces 5 and 6 takes place by means of adjustable strips 9 and 10. In the illustrated state, the medium dispensing device 1 is located inside the stencil 11 and the medium discharge opening 8 is in contact with the inner wall surface of said stencil 1.
The ejected medium passes through the perforations of the stencil and reaches the surface of the moving substrate 12 in this manner. The adjustment of the strips 9 and 10 is particularly time-consuming and delicate, and small deviations in adjustment as well as displacements due to lowering of the device can lead to a high degree of non-uniformity of distribution.

2A and 2B show a dispensing device according to a first embodiment of the invention, in which a device 20 with a body 21 is provided with dispensing spaces 22 and 23. FIG. The medium can flow in the downstream direction into the slit-like spaces 28 and 29, which spaces
and ends at 25. The slit is formed by plates 34 and 35, which are fixed on the central plate by means of fixing means 30 and 31, respectively, extending in this example over the length of the dispensing device. .
Plates 34 and 35 are in intimate contact with the inner wall surface of device 20 at one longitudinal end.

In the typical embodiment of the dispensing device shown in FIG. 2, the slit wall height is 45 mm and the slit width is 0.5 mm, and the quotient between these two parameters is therefore 90. For the devices described in the following description, depending on the dispensing needs, the entire length of the device with a constant slit wall height, maintaining a ratio of at least 25 between the slit wall height and the slit width. It is possible to adjust the slit width by changing the slit width according to a specific pattern, or, as described above, by changing the slit wall height according to a specific pattern while keeping the slit width constant.

FIG. 3 shows another embodiment of the apparatus, in which apparatus 40
has a device with medium distribution spaces 42 and 43 and a long slit-like space 46, in which the medium is
It flows from distribution space 42 to 43 in the direction indicated by arrow 44 and from there, as indicated by arrow 45, into a slit-like space 46. 4
7 indicates a spacer for keeping the width of the slit-like space 46 at a correctly adjusted value.

FIG. 4 shows yet another embodiment of the device of the invention. The device 50 comprises medium distribution spaces 51 and 52, which lead to slit-like spaces 53 and 54, which in turn open towards a collection space 57, from which the medium flows through the medium discharge opening 5.
It can flow out through 6.

FIG. 5 shows the substrate 72 being passed over the roll 71 and the doctor blade 74 being positioned at a small angular offset forward of a vertical plane passing through the axis of the roll. A media distribution device 60 with distribution spaces 63 and 64 is arranged in the upstream direction of the substrate, and a media supply line 6 is arranged in the distribution spaces 63 and 64.
1 and 62 are connected and the dispensing spaces 63 and 64 are arranged as described in connection with FIG. 4 above. The formed slit leads to a collection space 67, which terminates in an opening 75 for media release. The sliding piece 69, to which the side partitions 70 are connected, is accommodated in the collecting space. The connection between the rod-like part 68 and the side partition 70 is formed by a strip-like member accommodated in the collection space 67. sliding piece 69
By displacing the slit-like outlet, the slit-like outlet is first effectively confined, while the lateral bulkhead 70 on the substrate
This prevents the medium, such as expanded foam, from spreading more than necessary across the width of the moving medium. The required thickness of the coating layer is adjusted by a doctor blade 74.

FIG. 6 shows two graphs, for example, the amount of foamed medium applied in grams per minute on the vertical axis and the position along the length of the dispensing device on the horizontal axis. FIG. 6A shows the results of a conventional device incorporating two complementary slits, while FIG. 6B shows the results obtained using the device of the invention. In FIG. 6A it is evident that the result of media application is not uniform, while in FIG. 6B it can be seen that the dispensing device of the present invention provides a very uniform media application transverse to the length of the device. It will be done. From the above-mentioned embodiments of the device of the present invention,
It will be appreciated that the media outlet surface is often followed by a media collection space in which the slit-like media discharge openings are located. However, such a collection space is not always necessary, and the medium outlet opening can in certain cases be formed by a medium outlet surface, in other words by a flow slit in a slit-like space. .

ADVANTAGES OF THE INVENTION The dispensing device of the invention has an outflow slit connected to a media distribution space and an opening for the release of the media fed from the slit. Furthermore, the outflow slit has a wall that defines the range of the outflow slit seen in the flow direction of the medium (the height of the slit wall surface) and is at least 25 times the width of the slit. It is configured to distribute to the base material while in contact with the surface.

In this distribution device, the pressure fluctuations of the medium are absorbed by the frictional resistance of the medium while the medium passes along the slit wall of sufficient length, and the passage from the outflow slit to the medium discharge opening is The medium is discharged under pressure by the medium discharge apertures coming into contact with the substrate surface, thereby making it possible to uniformly distribute the medium to the substrate under a uniform distribution pressure. In addition, since the slit width is adjusted under the sufficiently long slit wall, conventionally, the slit width is easily changed due to pressure fluctuations in the medium, distortion of the device due to external force, or temperature changes. The drawbacks of slit adjustment have also been resolved.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view showing a conventional distribution device, Figure 2 is a vertical sectional view showing a conventional distribution device;
The fifth figure shows an embodiment of the present invention, and the second figure shows an embodiment of the present invention.
Figure A is a vertical cross-sectional view of one example, Figure 2B is a cross-sectional view thereof, Figure 3 is a vertical cross-sectional view of another embodiment, Figure 4 is a vertical cross-sectional view of yet another embodiment, and Figure 5 is a further A vertical cross-sectional view showing another embodiment together with a doctor blade;
FIG. 6A is a graph showing the state of the coated surface when distribution is performed using a conventional device, and FIG. 6B is a graph showing the state of the coated surface when distribution is performed using the device of the present invention. 3, 4... Space for media distribution, 11... Stencil, 22, 23... Space for media distribution, 2
4, 25... Outflow slit, 30, 31... Spacer, 4, 35... Plate, 42, 43... Space for medium distribution, 46... Slit-shaped space, 47... Spacer, 51, 52... Medium Distribution space, 56... Media release opening, 58...
Stencil for screen printing, 63, 64...space for media distribution, 67...collection space, 69
... Sliding piece, 70 ... Side bulkhead, 72
... Base material, 74 ... Doctor blade, 75 ...
Media distribution opening.

Claims (1)

[Claims] 1. For a web-shaped base material that moves in a direction substantially perpendicular to the axial direction of a device that is entirely rod-shaped,
A device for uniformly distributing a viscous medium across the width of the substrate, the device comprising: a medium supply means; at least one medium distribution space; an outflow slit connected to the distribution space; and a medium fed from the slit. the dimensions of the wall defining the range of the outlet slit (height of the slit wall surface) as seen in the direction of flow of the medium, and comprising a medium discharge opening for dispensing onto the substrate while in contact with the surface of the substrate; ) is at least 25 times the width of the slit. 2 The height of the slit wall surface is 50~50% of the slit width.
Device according to claim 1, characterized in that it is 150x. 3. Device according to claim 1 or 2, characterized in that one or more spacers extend over the width of the slit and are free of sharp edges. 4. An apparatus characterized in that the spacer is located on the upstream side of the outflow slit in the upstream direction of the viscous medium at a distance of more than half the height of the slit wall surface. 5. The area of the outflow slit is limited in the direction perpendicular to the outflow direction of the medium by blocking means located in the collection space leading to the outflow slit. Device. 6. Device according to claim 5, characterized in that the blocking means are formed by a sliding piece fitted into the collection space. 7. The blocking means are formed by a short sliding piece fitted into the collecting space, and the remaining length required in the direction of the device is formed by a flexible hose that can be expanded for the blocking action. The device according to claim 5 or 6, characterized in that: 8. The device according to claim 6 or 7, wherein one or two of the sliding pieces are attached to a partition wall extending vertically on the upstream side of the substrate that moves on the substrate. 9. The apparatus of claim 1, wherein a media dispensing device cooperates with a rotating printing stencil for dispensing media onto a moving substrate, and wherein the media ejection aperture abuts an inner wall of the stencil. 10. A media dispensing device as claimed in claim 1, wherein the media dispensing device cooperates with a doctor blade for dispensing media onto a moving substrate, and wherein the media ejection opening is located upstream of the blade. equipment.